Stalker Minionbrain

Based on game build 714014 | Last updated: 2026-02-27

Overview

The stalker_minionbrain component implements a finite state machine using a Behavior Tree (BT) to govern stalker minions (small entities summoned by the Stalker boss). Its primary responsibilities include maintaining leash distance relative to the Stalker, idling while near the Stalker, and initiating self-destruction after a randomized delay following the Stalker's death. It depends on the EntityTracker component to locate the associated Stalker and the Health component to terminate the minion.

Usage example

This component is typically added to minion entities during their initialization, usually via a prefab definition or spawner logic. Example (conceptual; actual instantiation occurs in prefabs like stalker_minion):

local function fn()
    local inst = CreateEntity()
    inst:AddComponent("stalker_minionbrain")
    -- The brain automatically initializes on `OnStart`, no manual call needed.
    return inst
end

Dependencies & tags

Components used:

• entitytracker — accessed via inst.components.entitytracker:GetEntity("stalker") to retrieve the Stalker target.
• health — accessed via inst.components.health:IsDead() and inst.components.health:Kill() for lifecycle management.

Tags: None identified.

Properties

No public properties are explicitly initialized in the constructor.

Main functions

StalkerMinionBrain:OnStart()

• Description: Initializes the Behavior Tree (BT) root node. Defines the logic flow: (1) panic if triggered, (2) enforce leash to Stalker, (3) stand still while Stalker is present, (4) wander during a post-Stalker-death grace period, and (5) kill the minion once the grace period ends. This function is automatically invoked when the entity enters the world.
• Parameters: None.
• Returns: nil.
• Error states: None. Assumes EntityTracker and Health components are present.

GetTarget(inst)

• Description: Helper function that retrieves the Stalker entity via the EntityTracker using the "stalker" key.
• Parameters:
  • inst: The entity instance whose EntityTracker component is queried.
• Returns: entity inst or nil — the Stalker entity, or nil if not tracked.
• Error states: Returns nil if the Stalker is not registered in EntityTracker.

GetTargetPos(inst)

• Description: Helper function that returns the current world position of the Stalker target, if available.
• Parameters:
  • inst: The entity instance whose EntityTracker component is queried.
• Returns: Vector or nil — the Stalker's position, or nil if the target is absent.
• Error states: Returns nil if GetTarget(inst) returns nil.

ShouldDie(self)

• Description: Determines whether the minion should proceed to die. If no delay has been set (i.e., self.delay == nil), it calculates a random delay based on whether the Stalker is already dead (stalkerdead flag), adding randomness for unpredictability. Returns true only when the current game time exceeds the computed delay.
• Parameters:
  • self: The brain component instance.
• Returns: boolean — true if the delay has elapsed and the minion should die; otherwise false.
• Error states:
  • Sets self.delay lazily on first invocation if not present.
  • Delay = stalkerdead ? [1, 3] or [3, 5] (i.e., dt + math.random() * dt where dt is 1 or 3).

Events & listeners

None. The component uses behavior tree nodes and direct state queries instead of event-driven logic.

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